Detent mechanism



Nov. 14, 1939. M. BIRKIGT 2,179,914

DETENT MECHANISM Filed Jan. 4, 1938 wav' INVENTOR 222m @ggf 4 u BY R gm ATTORNEYS Patented New. lid, 11939 nutren g sra-ras Nr ormeg- Application anuary 4, 1938, Serial No. 183,343 En Luxemburg .inne 21, 1937 s claims. (ci. ca -1) i The present invention relates to detent mechanisms, this expression designating, .in this case, the means for releasing a movable member subjected to the action of a high return force, and it is especially, although not exclusively, concerned with mechanisms of the type in question used in `connection with breech mechanisms of nrearms. n

The chief object of the present invention is to provide a mechanism' of the type above referred to which is stronger and more reliable.

According to the essential feature of the present invention, a detent mechanism of the type F above referred to is devised in such manner that while the movable member which is to be caught bythe catch element is nearing the end of the stroke which brings it into the position in which it is to be stopped, means are brought into play for compelling, if necessary, said catch to engage fully into the notch provided for this-purpose in the movable member.

According to another feature of the present invention, relating to mechanisms of the type above referred to in which said movable member or breech has an axial displacement, the catch element is movably carried' by a sliding part adapted to undergo a limited axial displacement parallel to that of said movable member or breech, the means for forcing the catch element fully into the corresponding notch of said movable member or breech being adapted to perform this function completely before said sliding part reaches the end of its axial displacement. According to still 'another feature of the pres- .ent invention, the means for forcing said catch element into said notch consist of cam means operative by the axial 'displacement of said sliding part with respect to the stationary part of the structure, the catch member being for instance provided with an inclinedsurface adapted to ccoperate with a roller carried by said stationary the parts in a different relative position, corresponding to another ,period of the operation.

In the following description,v the mechanism according to the present invention is shown as applied to an automatic firearm of the open 5 breech type, including, among other parts, a movable breech I, subjected to the action of a return spring 2.

It is'known, in a general manner, that such a detent mechanism'as that with which the invention is concerned must be capable of stopping and holding the breech i in a position corresponding to the beginning of its return stroke. In existing detent mechanisms, there ywas pro; vided for this purpose a catch member which, under the action of a detent control, was caused to project across the path of a stop carried by the movable breech. Now, it happened sometimes that said stop came into-contact with the catch before the latter had fully projected across the path of said stop. Therefore, the catch member and the stop contacted each other along a relatively small area, which, in the long run, produced a serious wear and tear of said catch member due to the value of the pressures Vper unit of areaacting upon said contacting surface of re,- duced area.

According to the chief feature of the present invention, these drawbacks are obviated by arranging the detent mechanism in such manner that, when breech I is nearing the point at which its movement is to be stopped, means are brought into play for compelling, if necessary, the catch member 3 of the detent mechanism into full engagement 'with the notch 4 provided in said breech for said catch 3.

For instance, according to an embodiment of the invention, I can mount the catch member 3 on a support 5 capable of sliding' parallel to breech I, in slideways 5', and can provide an arrangement to cause the stopping. of said breech to take place in two periods, to wit:

a. A first period, in the course of which breech I drives support 5 against the action of at least one spring 6, the relative displacement of said support with respect to the stationaryparts 'I- of the arm bringing into play the means which are to'compel catch member 3 to engage fully into notch 4;

b. A second period, in the course of which the whole of the sliding system including support 5 and catch member 3, fully engaged in the notch 4 of breech I, strikes a shock absorbing system constituted, for instance, in the known manner, by a stop 8 of ber or rubber.

In other' words, during the ilrst period, the catch is brought into engagement with the corresponding notch oi the breech through the usual means and, at the beginning of this period, the engagement may be imperfect, the two parts contacting each other along a surface which may be relatively small, but this creates no diiiculty because, as the catch can movel axially together with the breech, the pressure applied to said relatively small surface is small. In the course of the axial displacement thus transmitted to' the catch by the breech, the means for fully engaging said catch into the notch of the breech are brought into play, and when the catch is stopped, thus stopping also the breech, the thrust exerted by said breech on said catch is applied through a sufiiciently large surface.4

Concerning the means above referred to, 'they are, Vof course, devised in accordance with the kind of mechanism employed for controlling the action of catch member 3.

In the embodiment shown by the drawing by way of example, catch member .3 consists 'of a kind of hook pivotally mounted on the sliding support 5 'and subjected, on the one hand, to the action of a spring 9 tending to apply it against the bottom of a groove' If in the breech I, the rear vend of which groove constitutes the notch above referred to. On the other. hand, catch member 3 is subjected to the action of a control rod i0, through which it is possible to move said catch member away from said breech. This rod l0 engages in a slot 3| provided in catchmember 3, in such a manner as toA permit the axial sliding displacements of said catch member.

Now, the means for positively bringing said catch member 3 into full engagement with notch 4 include, in this embodiment, a roller Il carried 1 by the stationary part I of the arm, and an -ment of inclined surface 32 with roller I I.

inclined surface 32 carried by catch member 3 and adapted to cooperate with said roller, said inclined surface and said roller being dimensioned and positioned in such a manner that, when sliding support 5 comes into contact with elastic stop 8 (position shown in Fig. 2 of the drawing), catch member 3 has been fully applied against notch 4 as 4a consequence of the engage- Therefore the contacting surface between catch member 3 and notch 4 has reached its maximum value when the breech is about to be stopped by the catch member.

Of course, it will be readily understood that, while the roller is carried by the stationary part and the inclined surface by the catch member, this is but an example, the true condition 'being that the roller is carried by one ofthese two parts and the inclined surface by the other one.

In any case, the pa'rt oi' catch member 3 which is to cooperate with notch 4 is advantageously given the shape of a circular arc having its center on the axis o about which said catch member is pivoted to the sliding support 5, in such manner that when said catch member isdisengaged from the notch, it is not necessary to cause breech I to move backward against the action of spring 2. f

It should be noted that the spring 6 which urges sliding support 5 away from stop 8 should be chosen of a strength slightly greater than that of the breech spring 2, and in any. event suiilcient for compelling the whole of the sliding parts, including breech I, sliding support 5, and of course catch member 3, to move backward, after the stopping or the forward movement of the breech, against the action oi' spring 2,soastobring thesepartsintoapositionin which catch member 3 is disensed from the means which had positively brought it into full engagement with notch 4. Therefore, in this iinal position catch member 3 is ready to be again operated for releasing the breech.

Whatever be the embodiment that is chon for the detent mechanism for firearms according to my invention, the operation and advantages of this mechanism result sun'iciently clearly from the above explanations ior making it necessary to further describe them.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eiiicient embodiments oi the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present 4'invention as comprehended within the scope of the accompanying claims.

What I claim is:

l. In connection with a structure including a stationary. part and a movable part slidable with respect to said stationary part, a releasable locking mechanism which comprises, in combination. a sliding support mounted on said stationary part for movement parallel to the direction of movement of said movable part, catch means movably carried by said sliding support, means for limiting the displacement of said support to a short amplitude, and means, operative by the movement of said sliding support relative to the stationary part, for positively vengaging said catch means with said movable part before said movable sliding support is stopped by said limiting means.

2. In connection with a rettrml including a stationary part andv a movable breech, a releasable locking mechanism which comprises, in combination, a sliding support mounted on saidstationary part for movement parallel to the direction of motion of saidl movable breech, a catch member movably mounted on said sliding support adapted to engage said breech for stopping the sliding movement thereof, yielding'means for stopping thesliding displacement of said support, and cooperating means carried by said stationary part and said catch member operable by `the movement of said sliding support relative to the stationary part for positively engaging said catch member with said breech during move-l ment of said sliding support.

3. In connection with a iirearm including a stationary part and a movablebreech, a releasable locking mechanism which comprises, in combination, a sliding support mounted lon said stationary part for movement parallel to the direction ci motion o! said movable breech. aoatch member 'movably mounted on said sliding support adapted to engage said breech for stopping the.v sliding movement thereof, means for oontrolling said catch member. resilient means i'or urging said catch member toward its position of engagement with said breech, means for limiting the sliding displacement of said support, and cooperating means, carried by said stationary part and said catch member operable by the movement of said sliding support relative to the stationary part for positively engaging said catch member with saidbreech during the movement oi.' said sliding support.

4.-In connection with a firearm including aV stationary part and a movable' breech, a rehas- 'able, locking mechanism which comprises. in combination, a. sliding support mounted on laid 1 stationary partfor movement parallel to the 5 tively and operable by the movement of said sliding support relative to the stationary partfor said catch member with said positively engaging of said sliding supbreech during the movement port. v

5. In connection with a firearm including a stationary part and a sliding breech carried by said stationary part, a releasable locking mechanism which comprises, in combination, a sliding support mounted on said stationary part for movement parallel to the direction of motion of saidmovable breech, a catch member pivotally mounted on said sliding support adapted to engage said breech for stopping the sliding movement thereof, operating means for controlling said catch member, spring means for urging said. catch member toward its position of engagement with said breech, spring means for urging said sliding support away from said stationary part in the direction of the sliding movement thereof opposed to the direction in which said breech is moving `when it is to be stopped by said 'catch member, a, stop for limiting the movement of said sliding support in the other direction of movevment thereof, and cooperating means carried by' said stationary part and said catch member, respectively, and operative by the movement of said slidingsupport relative to the stationary part for positively engaging said catch with said breech when said sliding support is being moved against the action ofthe last .mentioned sprin means and before it strikesv said stop.- -f

6. A releasable locking'mechanism according to claim 4 in which the cam means carried by said catch member and said stationary part, respectively,"inc1ude an .inclined surface carried by one Vof these two last mentioned members and a roller carried by the other adapted to roll on said inclined surface.

7. A eleasable locking mechanism' according to claim 4 in which the cam means ,include an inclined surface carried by .said catch member.- and a roller carried by said stationary part adapted to engage said inclined surface.

8. A locking mechanism according to claim 5 wherein the stop isresilient.

/ t MARI! BIRKIG'R 

